Ocean updates served in stragglers, flocks, and set waves

Archive for July, 2006

The seafloor off Santa Barbara just burped up a huge eruption of methane – and scientists caught it on video. Now, at about 5,000 cubic feet at the surface, this methane cloud was huge by people-watching-with-videocameras standards. That’s not to say massive by vast-limitless-ocean standards. But still, it gave the scientists a chance to do some number-crunching on an imaginary massive eruption of methane.

And why are the scientists stretching their imaginations in this way, you might ask? Well, it turns out that there are actually massive (not just huge) deposits of methane on the ocean floor (and in Arctic permafrost, too, but that’s another story). The ocean deposits are quiescent at the moment, frozen into sort of waterlogged crystals called methane hydrates, a.k.a. clathrates (here’s a bit more blogging on clathrates). But it takes a lot of cold combined with a lot of pressure to persuade methane gas to lead a quiet life as a crystal.

At a glance, ocean bottoms are great places for cold and pressure. Except in a warming world. There’s evidence from studies of the last 100,000 years or more that methane has fizzed en masse into the atmosphere at the same time that the Earth’s temperature has warmed dramatically.

As you might expect for people peering back through the millennia at an invisible gas, scientists have had a hard time deciding whether methane surfaced because the world heated up (melting the crystals) or whether the world heated up because great clouds of methane surfaced. But methane is a powerful greenhouse gas. Although it doesn’t persist in the atmosphere as long as carbon dioxide, it traps much more heat (some 20 times more, by some measures) while it’s there.

We can do the math ourselves: If ocean temperatures warm enough to melt the methane clathrates, great quantities of methane could fizz up into the atmosphere, where they would add to our already pressing greenhouse gas woes. We might get a firsthand look at what happened in previous periods of warming: something happened to destabilize the clathrates (ocean warming? a drop in sea level? submarine landslides?), discharging gobs of methane into the atmosphere which then kick the climate into an even more strenuous cycle of warming. That, in a nutshell, is what they call the Clathrate Gun Hypothesis, as proposed by James Kennett of UC Santa Barbara.

What’s really intriguing about the new video and analysis of the (merely huge) burp is that scientists haven’t been content with such an armwavey doomsday scenario. In time-honored science tradition, they looked at a new hypothesis and immediately started trying to poke holes in it. Wouldn’t methane bubbles dissolve back into the water – or react with it – before they ever reached the air and started trapping heat? Experiments with methane seeping slowly into water suggested that small bubbles did indeed re-dissolve.

But the careful measurements coming from the video suggest that very large emissions isolate most of the methane from the water and carry much of the gas (i.e., 90 percent of it from 250 meters depth) to the surface undisturbed. Call it what you want – I think of it as a fizzing gun – the sobering part is that our own CO2 emissions, copious as they are, may just wind up pulling the trigger on the clathrate gun.

Earlier this summer, Californians were alarmed to find sick or dead pelicans washing ashore in unusually high numbers. More than a hundred were reported from beaches between Santa Cruz and Monterey and around Ventura.

Granted, this is old news – even the New York Times covered it a month ago. But last week I was out at Garrapata State Park south of Carmel and saw this one doing a creditable impression of Archaeopteryx. It’s a sad sight when you’re used to seeing your pelicans stretched across the face of a wave and funneling down the line, or spread high against the blue sky in fat chevrons, lumbering into the sunshine. Then today I saw another, this one up in the low dune vegetation above the high tide line, in Moss Landing.

News reports are proffering a couple of explanations for the apparent mass die-off: it’s either domoic acid poisoning from harmful algae (causing drunk pelican syndrome), or starvation. The California Dept. of Fish and Game came down on the side of starvation, noting that lab tests had not been able to find any signs of poisoning. Starvation had more evidence going for it. This year saw lots of successful breeding among pelicans, and state biologists think this meant a burgeoning crop of young pelicans that suddenly found themselves unable to find enough to eat. Personally, I think that’s a bit of a stretch: are fish stocks really so low that pelicans are dropping dead? There’s no mention of other seabirds starving to death. Or large, baitfish-eating fish, either, for that matter. (Hundreds of baby terns in Los Angeles died when someone hosed their nests off an abandoned barge, but that’s different.)

The Fish and Game’s explanation does have one bit of evidence going for it: all 140 or so washed-up pelicans have been so-called young-of-the-year, only 2 to 4 months old. Essentially, they’re the feathered equivalent of puppies – not exactly deft even by a pelican’s somewhat ungainly standards. The thinking goes that if anybody is going to lose out in the struggle for food, it’ll be these gawky adolescents.

With great strings of healthy pelicans on show at nearly any state beach, it’s easy to treat this mystery lightly. But we shouldn’t forget that brown pelicans were nearly wiped out by DDT in the 1970s and they’re still listed as endangered. For all their lovable goofiness, I’d like to see them continue their swing back from that brink.

Heermann’s gulls are the coolest of all gulls. Sooty-bodied, creamy headed. Bright red beak. Completely mod. And where most immature gulls are a mess of brown mottles, adolescent Heermanns wear all sooty black, like they’ve been listening to the Cure. You could call them pirate gulls, perhaps, as if they’ve been off somewhere giving their leaders the Black Spot (read Treasure Island) and wound up covered in charcoal dust from it.

And, come to think of it, they have been off somewhere else – they’ve only returned to NorCal in the last few weeks. It’s a strange migration pattern – bass-ackwards, really – where the gulls actually fly south to Baja California to breed, then come back up here for the rest of the year. In early fall you can see thousands just offshore in the afternoons, grouping up and looking for food like so many beach flies on a piece of stranded kelp.

And there’s the final tip-off: Baja California. Scammon’s Lagoon. It must be there, to that gray-whale-choked bay 400 miles south of San Diego, where these pirate gulls retreat to bury their booty and raise the kids. Rockin it patch-eyed, peg-legged, plank-walking, cold-blooded buccaneer style. Watch how they’ll buzz a pelican that has just caught a fish, and you’ll see what I mean. This one’s looking out for jolly rogers from Pt. Lobos, Calif.

By now you probably know that yet another underwater earthquake has kicked up yet another tsunami that has struck yet another Indonesian island. At surf.bird.scribble, our hearts go out to the 50,000 Javans displaced and several hundred killed by the six-foot wall of water.

God knows we could all use an early warning of a tsunami, but let’s just have a quick recap of the problem: What we’re trying to do is to notice a major earthquake happening deep in the Earth’s crust out in the middle of the ocean, and then issue some kind of panic alert that outraces the 500-mph tsunami wave and reaches only those coast-dwellers and sunbathers in the tsunami’s path.

Oh, and we have to deal with human nature, too. A 2005 earthquake off the U.S. West Coast sparked a formal tsunami alert for pretty much all of coastal California…and almost no one listened. The only folks that took it seriously were some (not all) of the residents of Crescent City, a NorCal town that learned its lesson in 1964, when it was hammered by a tsunami from the magnitude 9 Good Friday earthquake in Alaska.

In 2005, I was in Santa Cruz, approximately 13 feet above sea level, and I didn’t hear about the tsunami warning until the news reported that it had been lifted. And there I was in the most insanely connected state of the wired-to-the-gills United States. Yesterday’s earthquake was only about 270 km off Java, and the tsunami arrived in about a half-hour. So I’m not saying we shouldn’t try to give warnings, I’m just saying the problem needs a lot of work.

Good old NOAA is doing its best to protect the Pacific coast of the U.S. They’ve deployed a dozen special tsunami-measuring devices in key parts of the ocean. (They’re called tsunameters. more about them here) A sensitive pressure recorder sits on the ocean floor and somehow detects the pressure from a tsunami wave passing several miles overhead. When and if this happens, the tsunameter beams an alarm to a nearby buoy, which forwards the news by satellite to a NOAA desk, where, as I imagine it, a red light starts flashing, people start shouting at each other, and someone calls the President.

In the meantime, NOAA is trying to get the word out to residents of the Pacific Northwest that they are sitting more or less at the end of a shotgun barrel. The Cascadia subduction zone lies less than a hundred miles off Washington and has a history of producing major tsunamis. The last one was in 1700, when it pitched a tsunami at Japan big enough to make their history books.

Like the Java tsunami, a tsunami from Cascadia would hit Washington and Oregon in 30 minutes or less. Unlike the 7.7 quake off Java, the Cascadia fault could be in the magnitude 9 range, or some 50 times more powerful. In that case, I take heart in NOAA’s last-ditch warning method: “If you feel violent shaking for several minutes, head for higher ground. The earthquake is your warning.”

Already, the warmer water temperatures have been blamed for the arrival of the long-spined sea urchin. Scads of these invasive aquatic pincushions have moved into the (not quite so) cold waters and laid waste to the $150 million (Australian) abalone fishery. Interestingly, the long-spined sea urchin’s southern range extent, until recently, was around Sydney. That’s ABOUT 500 MILES NORTH of Tasmania.
And this news hits me fresh off a showing of An Inconvenient Truth, where Al Gore fingers climate change as a disruptive agent that allows species to become invasive. And I thought he was stretching the point at the time.

Once again, the photo above is not the real long-spined sea urchin – to see one of these basketball-sized specimens click the urchin link above. My image comes, once again, from the NOAA Photo Library. Thanks, NOAA!

A swath of Namibian waters favored by fishing fleets seems to have been taken over by jellyfish – big ones, and lots of them. A new scientific survey found more than four times as much jellyfish (by mass) than fish in a 30,000 square mile stretch of once-prime fishing grounds. And 99% of the jellyfish sample was made up Aequorea forskalea, a once-rare whopper that can be a foot or more across and weigh as much as a wet chihuahua.

Now, I’m just as enthralled by jellies’ strange beauty as the next envious landlubber. But the sudden appearance of prizewinning jellies in Namibian waters seems to have come at the expense of fish stocks – perhaps even as a price of overfishing.

The Benguela current nourishes the Namibian waters with strong upwelling that brings nutrients to the surface and kick-starts binges of productivity by phytoplankton. That starts off a feeding frenzy among all the little copepods and other zooplankton, and the party continues all the way up the food chain until, in normal circumstances, you end up with shimmering schools of fat, happy mackerel, hake, and herring. (Kathleen Wong has a nice article on upwelling in the new Bay Nature.)

Overfishing subtracts, via nets wriggling with fish, a big, visible piece of this scenario. But it adds something too: scads of choice prey in the form of uneaten copepods, larvae and small fish. Enter the jellies. You can almost see them smiling and rubbing their tentacles together.

Research cruises in the 1950s rarely reported large jellies, as Christopher Lynam (Ph.D. student, University of St. Andrews, UK) and his coauthors note in this week’s Current Biology paper. Now, an estimated 12 million metric tons in the authors’ study area are clogging power plant intake pipes, covering fish catches with a layer of stinging slime, and even fouling diamond mining equipment.

The authors suggest a more worrying possibility, too. With scores of jellyfish eating fish food as well as fish larvae, the depleted stocks of market fish may not soon get the chance to rebuild their numbers. I suppose we can only wait and see. And start working on beer batter that makes jelly-guts taste good.

If you’re driving between the Bay Area and Monterey on US 101, try and do it during lunchtime. That way you’ll have a chance to order a carnitas burrito and a tamarindo jarrito (soda) at El Coyote Mexican Grill, less than 5 minutes off the Hellyer Ave. exit south of San Jose. Here’s Google Earth (click for a larger version). And directions.

Could it be that this place takes its name from the slang for one of those shady men who smuggle immigrants over the Rio Grande and into the land of opportunity? Because the carnitas at this place are steeped in sun-baked Mexican tradition. The giant flour tortilla has been grilled crispy, not steamed. The beans have been cooked down to a pearly brown syrup. Pale crescents of real avocado peek out in place of the usual thin green “guacamole.”

And then there’s the carnitas themselves. Cut into moist, dice-sized chunks and roasted, not stewed, until the grain comes out and the whole cube lists to the side under its own tenderness. Finally, finished with the slightest caramelization on the grill to coax out the most delightful pig-ness of the meat. Four dollars and fifty cents. I had half of mine for lunch; the other half for dinner.

Don’t ask me how I found it. I had wandered off the highway looking for gas. I saw the restaurant crouched next to a laundromat in the thin shade of an old strip mall. Somehow, I just knew.

Interesting side note: I picked up a free Spanish-language newspaper. Thick with ads, maybe 36 pages, tabloid size, it had one page each dedicated to news from most of the countries south of the border, down at least as far as Venezuela. Ads were all over the map, from sexy (well, sorta cheesy actually) nightclubs to real estate ads. Million dollar real estate ads. The country is changing, folks. I just pray they bring their carnitas with them.

About the Scribbler

Hugh Powell is a little weary of big-ticket items like Pluto, the Mars rover, and small fossilized humans getting all the science news coverage. Keep an eye out here for wisps and scraps you won't find anywhere else. Particularly about the ocean, which is really cool and, honestly speaking, much bigger than you think.